Cradle for top rolls of double apron drafting arrangements



n 1960 A. SCHILTKNECHT 2, 41,262

CRADLE FOR TOP ROLLS OF DOUBLE APRQN DRAFTING ARRANGEMENTS Filed Sept. 26, 1958 2 Sheets-Sheet 1 Fig. 7

INVENTOR. ADOLF SCH/LTKNECHF June 21, 1960 A. SCHILTKNEC HT 2,941,262

CRADLE FOR TOP ROLLS 0F DOUBLE APRON DRAFTING ARRANGEMENTS Filed Sept. 26, 1958 2 Sheets-Sheet 2 INVENTOR. AoaLF SCH/LT'KNECHT'.

States Patent Qfi ce Patented June 21, 1960 CRADLE FORTOP ROLLS or DOUBLE APRON DRAFTING ARRANGEMENTS Adolf Schiltknecht, Winterthur, Switzerland, assignor to Job. Jacob Rieter & Co. Ltd., Winterthur, Switzerland, a corporation of Switzerland Filed Sept. 26, 1958, s'er. No. 763,689

Claims priority, application Switzerland May 18, 1955 5 Claims. (Cl. 19-131) The present invention relates to a cradle for double apron drafting arrangements in spinning machines.

The present application is a continuation-in-part application of my copending application Serial No. 57 9,848, filed April 23, 1956, now abandoned.

Cradles for double apron drafting arrangements are known which are directly or indirectly connected with the top roll carrier or which are loosely suspended from the axle of the top roll-pair and are held in place only by aprons looped around the top rolls. Cradles for the upper aprons of double drafting arrangements are known which are adapted to yieldingly change the distance between the point of reversal of the apron and the axis of the top roll by the action of a spring which counteracts the tension of the apron.

All conventional systems have the disadvantage of inaccurate parallelism of the reversal bar of the cradle relatively to the axis of the top roll pair so that the aprons contact the lateral guides of the cradle and run thereonto. This renders the tension and the running of the upper apron ununiform and disturbs guidance of the fibre bundles between the upper apron and the lower apron with all the undesired consequences known only too well to the operators of spinning machines.

It is an object of the present invention to provide a cradle for the aprons of a top roll pair of drafting arrangements of a spinning machine which cradle maintains accurate parallelism of the axis of rotation of the top roll pair with respect to the linear reversal guide for the upper apron at all operating conditions and which avoids the aforedescribed disadvantages of the conventional systems. With the cradle according to the invention the optimal tension of the upper apron which tension is required for faultless drafting, is reliably maintained.

The top roll cradle according to the invention is provided with two brackets connected with the rigid apron reversal bar and adapted to rest on the axle intercom necting the two top rolls. The sides of the brackets facing the top rolls are individually provided with a bearing for the top roll axle, the bearings being rigidly spaced from the line at which the apron contacts the reversal bar, each bearing including two fiat surfaces on which the axle rests, the planes of the surfaces preferably forming an acute angle and being parallel to the linear line of contact between apron and reversal bar and thereby accurately maintaining the position of the axle of the pair of top rolls in parallel relation to the line of contact of the apron with the reversal bar of the cradle due to the effect of the tension of the apron.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of a modification thereof when read in connection with the accompanying drawing in which:

Fig. l is a top view, looking at a right angle to the drawing field, of a cradle according to the invention resting on the axle of a pair of top rolls.

Fig. 2 is a large scale sectional view of the device shown in Fig. 11, the section being made along line II-II in Fig. 1.

Fig. 3 is a perspective view of a cradle according to the invention.

Fig. 4 is a large scale sectional view of the device shown in Fig. 1, the section being made along line IVIV in Fig. l, and including aprons and a saddle for supporting the top roll assembly and means for retaining the cradle in the desired position.

The same numerals designate the same parts in all figures.

Referring more particularly to the drawing, the cradle 1 is made of one piece and includes an apron guide portion 2 and a mountingportion 3 for holding the cradle 1 in proper position on a top roll assembly 5. Two aprons 4 are looped around the apron guide portion and the top roll assembly.

The apron guide portion 2 includes a reversal bar 6 8, 9 which prevent lateral movement of the aprons. The

mounting portion 3 includes two symmetric brackets 10, 11 which partly surround the top roll axle 12, a rigid axle retainingflap 13, 14, respectively, being provided on each bracket and in cooperation with the brackets prevent falling 01f of the top roll assembly located therebetween. Each bracket 10, 11 has a bearing surface positioned in a common plane B and each retaining flap 13, 14 has a surface 15, 16, respectively, positioned in a common plane A, the planes forming an angle a and being in absolutely parallel position with respect to the straight front edge 7. Each bracket has a somewhat yielding portion 10', 11', respectively, bent around the axle 12 and having an end portion of reduced width, the end portions being connected by a transverse bar 17.

In order to reduce undesired friction the yielding portions 10', 11 are bent at such a distance from the flaps 13, 14 that there is a clearance at the part c of the portions 10', 11 which clearance is so small that it is not visible in Fig. 2. The radius of the bends is somewhat smaller than that of the axle 12. This prevents contact of the mounting portion 3' with the axle 12 at undesired locations. The bearing surfaces 15, 16, Le, the plane A makes an angle a of about with the plane B of the reversing bar 6. The plane B in which the undeformed portions of the brackets 10, 11 are located is placed at an angle ,9 of about 95 with respect to the plane in which the yielding portions 10', 11 are located. Though an angle ,3 of about 95 is shown in the drawing, experience has shown that an angle 19 of, about is preferable to avoid undue stress on the brackets when inserting or removing the top roll assembly. The desired result is obtained as long as the angle a is smaller than the angle 5. This structure produces a seat for the axle 12 which seat converges towards the open side of the seat and forms a part-enclosure for the axle. The latter can only be removed from its seat by outwardly bending or deforming the portions 10, 11' until the axle passes the points 18, 19, respectively, of the flaps 13, 14, as shown in dash-dot lines in Fig. 2. After removal of the axle 12 the elastic portions 10', 11 snap back into the undeformed position shown in solid lines in Figure 4 is a more complete illustration of the support of the cradle 1. A spring 31 is connected in the conventional manner with a saddle 30 supporting the top roll assembly 5, the spring 31 having end portions which are inserted in suitable recesses 32 and 33 in the saddle 30. The spring 31 is provided with an extension 34 which is placed around the forward end 35 ot the saddle 30 and has a looped end 36 which slightly presses against the top of the reversal bar 6. This prevents lifting of the bar 6 and rotation of the cradle 1 in the direction of movement of the apron 4. For proper spacing of the reversal bar 6 from the lower aprons 37 a spacer element 38 is mounted on a reversal bar 39 for the lower aprons 37 between the latter, the reversal bar 6 resting on the element 38. I

An accurate position of the apron according to the invention can be obtained simply by making the bearing surfaces for the axle of the top roller pair, i.e., the bearing surfaces on the faces 15, 16 and on the brackets 10, -11 exactly parallel to the line "of 'contact'of the apron Wlthlhfi! reversing bar 6. With the structure of the apron cradle according to the invention this can be done at a minimum of manufacturing cost.

What is claimed is: V

1. A cradle for the top aprons of a drafting arrangement of 'a spinning machine comprising an apron reversal bar, and two brackets laterally extending from said reversal bar and being adapted to rest on the axle interconnecting the two bosses of a top roll, each of said brackets forming a bearing for the top roll axle each of said bearings having two substantially plane bearing surface portions placed at an angle with respect to each .4 t other and in fixed parallel relation to the line of contact of the aprons with'said reversal bar.

2. A cradle as defined in claim 1 in which the angle formed by the planes of said plane bearing surface portions is less than 90 and more than 3. A cradle as defined in claim 1 in which said brackets include a curved portion extending through substantially around the top roll axle, the radius of said curved portion being smaller than that of the top roll axle.

4. A cradle as defined in claim 1 wherein each of said brackets includes a substantially flat portion parallel to the top roll axis and forming one of said plane surface portions and a flap member disposed at a substantially right angle to said fla't portion, said flap member having an edge placed in the plane of the other of said bearing surface portions.

5. A cradle according to claim 3 wherein the part of said brackets betweensaid curved portion and said reversal bar includes said bearing surface and is relatively rigid and the part of said bracketslextending beyond said curved portion distal of said bar is resilient in a direction normal to the top roll axis to afford temporary spreading of said last mentioned part from said bearing surface for mounting and demountin'g the cradle.

References c iea in the {tile or this patent UNITED STATES PATENTS 2,708,290 

